<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>
    <style>
        .bw1 a{
            color: green;
        }

        .bw2 ul li{
            color: red;
        }
    </style>
</head>
<body>
    <div class="bw1">
        <a href="">后代选择器</a>
        <a href="">后代选择器</a>
    </div>

    <a href="">后代选择器2</a>
    <a href="">后代选择器2</a>

    <div class="bw2">
        <ul>
            <li>111</li>
            <li>111</li>
        </ul>
    </div>

    <ul>
        <li>111</li>
        <li>111</li>
    </ul>
</body>
</html>